Re: [Xen-devel] [PATCH v3 4/8] x86/vm_event/monitor/cr: check for vm-event subscriber on domctl

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.07.16 at 18:15, <czuzu@xxxxxxxxxxxxxxx> wrote:
> On 7/6/2016 7:01 PM, Jan Beulich wrote:
>>>>> On 06.07.16 at 17:52, <czuzu@xxxxxxxxxxxxxxx> wrote:
>>> Also adjust returned error code for similar check from -EINVAL to more
>>> descriptive -ENOSYS (XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP).
>> I'm not sure that's more descriptive, and we really try to not use
>> ENOSYS for other than unimplemented hypercalls. EOPNOTSUPP
>> perhaps?
> 
> Well,  it's not quite an 'unsupported operation' and neither does the 
> toolstack user communicate an 'invalid value', he must just be noticed 
> that something (the vm-event subsystem) needs to be initialised before 
> the operation can be done.
> But I agree ENOSYS is not acceptable either (I only now see it signifies 
> "Function not implemented", my bad for not peeking at that before using 
> it, I expected differently).
> 
> What about ENODEV, i.e. "No such device."? We need an error code saying 
> "Device not initialised"...

Fine with me (almost anything other than ENOSYS would be).

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel